Casein-copolymeric styrene-maleic anhydride type compositions for and method of sizing textile warp yarns



United States Patent CASEIN-COPOLYMERIC STYRENE-MALEIC AN- HYDRIDE TYPE COMPOSITIONS FOR AND METHOD OF SIZING TEXTILE WARP YARNS Elmer Rossin, Melrose, Mass, assignor to Monsanto Chemical Company, St. Louis, M0., a corporation of Delaware No Drawing. Application February 16, 1951, Serial No. 211,450

15 Claims. (Cl. 117-139.5)

The present invention relates to textile sizing compositions and to the sizing of textile warp yarns particularly cellulosic Warp yarns for the purpose, among others, of improving the abrasion resistance and the weaving characteristics of such yarns.

It is one object of this invention to provide novel compositions for sizing textile warp yarns.

It is a further object of this invention to size textile warp yarns with a size which is economical and which provides sized warp yarns having high abrasion resistance and excellent weaving efficiency.

Still further objects and advantages of thisinvention will appear in the following description and the appended claims.

The present invention provides a textile warp sizing composition comprising essentially an alkaline aqueous solution of casein and a water-soluble alkali metal salt of a copolymer of styrene or a substituted styrene and maleic anhydride or alkyl half esters of maleic acid, in which the alkyl group contains from 1 to 3 carbon atoms, or mixtures of such anhydride and half esters. The casein and the alkali metal salt of the copolymer are present in the solute of the solution in a weight ratio between 70:30 and 30:70. In general, the sizing compositions of this invention comprise from about 2 to 8% by weight solids, of which from about 65 to 100% consists of the casein and the alkali metal salt of the copolymer. The composition preferably also comprises an alkaline peptizing agent as, for example, an alkali metal hydroxide or carbonate to assist in the peptization and dissolution of the casein. Such agent also assists in the removal of the size after the yarns sized therewith have been woven into a fabric.

The compositions of this invention may also comprise small amounts say from 0.01 to by weight, based on the composition of a preservative, that is a substance which will inhibit putrefaction of the casein as, for example, borax, sodium-2,4,Sirichlorophenate, sodium 0- phenylphen'ate, methyl or ethyl ester of p-benzoate, tertiary butyl derivatives of cresols, sodium pentachlorophenate and the like. Such preservatives are usually necessary if the aqueous compositions are to be stored for a considerable period of time. From about 0.01 to 10% by weight, based on the composition, of softeners or lubricants such as sulfonated or emulsified animal, mineral or vegetable oils may also be employed in the compositions.

The sizing compositions of this invention may be prepared in various ways. Thus, they are suitably prepared by mixing the casein and the alkali metal salt of the copolymer in the dry state in the proportions stated, either with or without the alkaline peptizing agent. Such dry mixtures are then dissolved in water prior to application to textile warp yarns in a slasher, either with or without the addition of the alkaline peptizing agent. For best results in dissolving the mixture. the alkaline peptizing agent is preferably added to the dry mixture of the casein and the alkali metal salt of the copolymer or to the water in whichsuch mixture is dissolved.

Another method of preparing the sizing compositions of this invention comprises dissolving the casein and the alkali metal salt of the copolymer in separate aqueous solutions and then blending 'the resulting solutions in such proportions that the casein and the alkali metal salt 2,697,672 Patented Dec. 21, 1954 of the copolymer are present in the final composition in the specified weight ratios.

Still another method of preparing the sizing compositions of this invention comprises first dissolving a copolymer of the type described, for example, a copolymer of styrene and maleic anhydride, in an aqueous solution containing an alkali metal hydroxide or alkali metal carbonate in an amount sufficient to form an alkali metal salt of the copolymer in situ and to provide an alkaline aqueous solution, after which the casein or an alkaline aqueous solution of the casein is added to form the sizing composition, the casein being added in amounts sufiicien't to provide the proper weight ratio of casein to alkali metal salt of the copolymer.

Other methods of preparing the sizing compositions of' this invention may be used and the methods described above are not intended to be exhaustive.

As mentioned previously herein, an alkaline peptizing agent is preferably employed in the preparation of the compositions to peptize the casein and aid in its dissolution. Such agent also serves to aid in the removal of the size from the yarn after the sizing composition has been applied to the yarns and dried, and the yarns have been woven into fabrics. As examples of alkaline peptizing agents which are useful in the compositions of this invention may be mentioned ammonia, triethanolamine and other strong amines, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and alkali metal carbonates such as sodium carbonate and potassium carbonate. Sodium carbonate and sodium hydroxide are preferred for this purpose. The amount of agent used is within the range of 0.01 to 35% by weight, based on the total solids of the composition. For best results, it is preferred to employ from about 5 to 25% by weight of such agent based on the total solids in the composition.

The pH of the sizing compositions of this invention may be varied to some extent, but the compositions should have an alkaline reaction, that is, a pH above 7.0. The particular pH of the composition will be primarily dependent on the type of textile warp yarn to which it is applied. Thus, in the case of natural and regenerated cellulose warp yarns as, for example, cotton warp yarns and viscose rayon warp yarns the sizing composition is suitably employed at a pH between 7.5 and 11.5, preferably at a pH of 8 to 10.5. In the case of cellulose derivative yarns which are sensitive to alkali the compositions are preferably employed at a pH between about 7.1 and 8.0.

The compositions of this invention have a considerably higher viscosity at temperatures of 60 to 80 F. and at the same solids concentration than aqueous solutions of casein per se or aqueous solutions of the alkali metal salt of the copolymer per se. The difference in viscosity is a function of the solids content of the composition at the temperatures specified above. In most instances at temperatures of 60 to 80 F. the compositions of this invention will have a viscosity from 10 to times greater than an alkaline aqueous solution of the casein per se or the alkali metal salt of the copolymer at equal solids concentrations and at a pH of 9.0 :L- 1.0. This synergistic efiect is at least partially due to a reaction between the casein and the alkali metal salt of the copolymer.

This synergistic efr'ect, moreover, is not confined to the increase in viscosity of the com ositions of this invention as compared to solutions 0 the casein per se as the alkali metal salt of the copolymer per se since a synergistic effect is also obtained with regard to the abrasion resistance and weaving efficiency of the yarns sized with the compositions of this invention as compared to yarns sized with casein per se or the alkali metal salt of the copolymer per se. Thus, the abrasion resistance of yarns sized with the compositions of this invention is materially and unexpectedly higher than the abrasion resistance of like yarns sized with casein per se or the alkali metal salt of the copolymer per se. The weavingefficiency of yarns sized with the compositions of this invention is also unexpectedly superior to the weaving efficiency of like yarns sized with casein per se O the alkali metal salt of the copolymer per se.

In order to obtain these synergistic etfccts, it has presently been found that the proportions by weight of the casein to the alkali metal salt of the copolymer in the solution is very critical. Thus, it is necessary to use the casein and the alkali metal salt of the copolymer in a weight ratio between 70 parts by weight of casein to 30 parts by weight of the alkali metal salt of the copolymer and 30 parts by weight of casein to 70 parts by weight of the alkali metal salt of the copolymer. Best results are obtained by using the casein and the alkali metal salt of the copolymer in a weight ratio between 60:40 and 40:60.

The casein employed in the compositions of this invention may be derived from any source and need only be soluble or finely dispersible in aqueous solutions of caustic soda.

The sizing compositions of this invention are unique in the sense that they have a high viscosity at normal room temperatures, that is, about 65 to 90 F., but have unex ectedly low viscosities at temperatures above 120 ThlS is of decided advantage in that the sizing composition can be readily applied at temperatures of 120 to 180 F., at which temperature they have a low viscosity and thus penetrate the yarns, but as soon as the yarn is removed from the size solution the size cools and the size coating on the yarn becomes very viscous and thus congeals on the yarn even before the yarns are dried. Qonseouentlv. there is no appreciable tendency for the s ze to run off or drip from the yarns after they leave the size box and before they are dried, with the result that the yarn is provided with a full. substantially uniform coating which has an exceptionally high resistance to abrasion. n the case of sizing solutions of casein per se or the alkali metal salt of the copolvmer per se, this effect is not achieved for the reason that if such solutions are used at low viscosities they tend to drip from the yarns before dryin and thus do not provide a full, uniform coating, or if they are employed at high viscosities they do not have go d penetration, and the size thus lacks the necessary adhesion.

The alkali metal salt of the copolymer as employed in the compositions of this invention may be prepared in various ways. In general. they are pre ared by first forming the co olymer and then neutralizing the copolymer by use of an alkali metal hydroxide or carbonate, preferablv an alkali metal h droxide. The neutralization may be carried out by stirring and heating the copolymer in the form of a finely divided solid with sodium hydroxide in the resence of small amounts of water, that is. considerably less water than is reouired to form a solution. The resultin product is sufiiciently dry and free fi wing to he used with casein in the form of a substantially dry mixture. The neutralization of the copolymer to form the alkali metal salt thereof may also be carried out by adding the finely divided copolvmer to an aqueous solution containin an amount of alkali metal hydroxide sufficient to provide an alkaline solution, with stirring and heating. If the dry salt is desired the solution 18 evaporated to drvness and the salt thus obtained is comminuted to the desired degree of fineness.

As examples of copolymers from which such alkali metal salts are prepared and used in the compositions of this invention may be mentioned the co olymers prepared by copolymerizing stvrene or substituted styrenes as, for exam le. nuclear substituted alkvl stvrenes such as nuclear substituted methyl styrene and dimethvl styrene or nuclear substituted halo-styrenes such as nuclear substituted chlor stvrene or dichlor styrene with maleic anhvdride or alkyl half esters of maleic acid, in which the alkyl roup contains from 1 to 3 carbon atoms. such as methvl. ethyl or pro vl acid ma eate and mixtures of such anhydride and half esters. The mol ratio of the styrene or substituted stvrene to the maleic components in the copolymer may be varied to some extent but is preferably in the range of 1:1 to :1. For best results the copolvmer preferably should contain eouimolecular pro ortions of the styrene or substituted styrene and the maleic components. The alkali metal salts emploved in the com ositions of this invention are preferabl prepared from copolymers of styrene and maleic anhvdride or copolymers of styrene and mixtures of maleic anhydride and methyl acid maleate. The preferred salts are the sodium and potassium salts of such copolymers.

The substituted styrene employed in preparing the copolymers described above are free of solubilizing groups such as sulfonic or carboxyl groups.

The copolymers described above are suitably prepared by mass polymerization wherein the styrene or substituted styrene monomer and the maleic component monomers are heated in the presence of a polymerization catalyst as, for example benzoyl peroxide, in the absence of $01- vents or diluents for the monomers.

The copolymers are also readily prepared by heating the monomers in the presence of a polymerization catalyst such as benzoyl peroxide and in an inert hydrocarbon liquid such as toluene or xylene, which liquid is a solvent for the monomer but a non-solvent for the copolymer. I

Still other methods of preparing such copolymers will be apparent to those skilled in the art.

The sizing compositions are applied to the textile warp yarns by immersing the yarns as they pass from a storage device such as a creel to a take-up device such as a beam and drying the yarns before they are collected on the take-up device. This may be accomplished on a slasher wherein the warp yarns are taken from a creel, passed through the sizing solution and thence through squeeze rolls where excess solution is removed, after which the yarns are dried by passing them through-a heated zone or over drying cans and are then collected on a beam. Other means may be used to apply the size to the yarn and to dry the yarn.

The sizing process is best carried out by maintaining the sizing composition at a temperature of to F. during the sizing operation. Higher temperatures may be used but there is no substantial advantage. At

temperatures below 120 F. the viscosity of the solution is quite high except at low solids concentrations of l to 2% by weight.

The amount of size applied to the warp yarns may be varied considerably by controlling the solids concentration of the sizing solution and by removing excess sizing solution, if necessary, by means of squeeze rolls.. The use of squeeze rolls is usually desirable, in any event, in order to obtain better penetration of the size solution in the yarn fibers or filaments and thus obtain better adhesion of the size to the yarn. In general, satisfactory sized yarns are obtained by applying from about 2 to 12% by weight of solids, based on the dry yarns. Best results are obtained by applying from about 2 to 8% by weight of size solids, based on the weight of the dry yarn and such amounts are preferred.

The sized yarns may be dried over a rather wide range of temperatures depending primarily on the nature of the warp yarn. Thus cellulose ester yarns are normally dried at relatively low temperatures, that is, between room temperature (about 75 F.) and 212 F. Temperatures up to 250 C. may be used in the case of natural and regenerated cellulose yarns or wool yarns.

The sizing compositions and processes of this invention are useful for the sizing of cellulosic textile warp yarn. By cellulosic is meant cellulose esters such as cellulose acetate and cellulose propionate, natural cellulose such as cotton, linen and the like and regenerated cellulose such as viscose rayon, cuprammonium rayon and saponified cellulose esters such as saponified cellulose acetate. The sizing processes and compositions of this invention are especially suitable for the sizing of regenerated cellulose textile warp yarns, as, for example, filament and'staple fiber viscose rayon, cuprammonium rayon and saponified cellulose acetate textile warp yarns. In the sizing of such regenerated cellulose textile warp yarns it has presently been found that the abrasion resistance and weaving efiiciency of regenerated cellulose warp yarns sized with the sizing compositions of this invention are unexpectedly superior to the abrasion resistance and weaving efficiency of regenerated cellulose warp yarns which have been sized EXAMPLE I A. Preparation of sizing composition Ten parts of powdered sodium salt of styrene-maleic anhydride-methyl acid maleate copolymer (containing 54% combined styrene, 37% combined maleic anhydride and 9% combined methyl acid maleate) were dissolved in 90 parts of water byvmechanicailly stinriing the mixture at a temperature of 90 C. for 30*;minutesw On: cooling to 25 C., the solution-had a-pfi of 8.1 and a viscosity of 78 c'entipoises as measured by a Brook-field viscometer.

Ten parts of powdered casein,- 0.5 part of sodium hydroxide and 89.5 parts of water at 20 C. were mixed together and allowed to stand for minutes; This mixture was then heated, with occasional stirring, on a water bath and at a temperature of 60 C. until thecasein: was dissolved. On cooling to 25 C, the solution had a-pH of 9.9, and a viscosity of 37 centipo'ise's as measured by a Brookfield viscometer.

The solution of the sodium salt or the styrene-metals anhydride-methyl acid maleate copolymer and the solu' tion of casein, as repared above, were mixed together with stirring at a temperature 61' 25 C. A-homogeneeus viscous solution was obtained which contained 5% casein solids and 5% of the opolyiner salt solids. This solution had a viscosity of 6800 eentipoises atZS C. as measured by a Brookfield viscometer and had a pH of 8.5. The viscosity of this solution was thus at least 850% greater than the viscosity, of the casein soliit ion per se or the copolyiner salt solution perse' at the same temperature andsolids concentration. On heating the solution to a temperature of 60 to 70 C. (140 to- 158 F.) the vis cosity of the solution dropped to 1 centip'oises.

The solution containin 5% casein solids and 5% of sodium salt of styrene-maleic anhydride methyl acid maleate c'opolym'er solids, as prepared in the preceding paragraph, was diluted with waternmil it contained 3% casein solids and 3% of the cop'ol-yrn'er solids. The resulting compositionjwas then used as a sizing composition according to the following examples.

EXAMPLE II The sizing composition containing 3% casein solids and 3% of the copolymer salt solids, as prepared in Example I,- was charged to a size boX in a slasher and heated to a temperature between 140 and 150 F.-

One hundred and fifty filament, forty denier viscose yarns were then passed through the size solution at the rate of 12 yards per minute and then squeezed between squeeze rolls at a pressure of 5 lbs. per linear inch. The wet yarns were next passed over 3- drying cans, each at a, temperature of 200 F. to dry the yarns, after which the yarns were taken up' on a beam.

One hundred and fifty filament, forty denier viscose yarns from the same lot were sized inthe same manner with a 6% solution of casein per se. The casein solution was prepared by first making up a 10% solution as described in the second paragraph of Example I and then diluting such solution with water until it contained 6% solids.

One hundred and fifty filament, forty denier viscose yarns from the same lot were sized in the same manner with a 6% solution of the sodium salt of the styrene maleic anhydride-methyl acid maleate copolymer. This sizing solution was prepared by first making up a 10% solution as described in the first paragraph of Example I and then diluting such solution with water until it contained 6% solids.

Each set of sized yarns, as prepared above, were tested on a Duplan adhesion tester for abrasion resistance with the following results:

The above table shows that the yarn sizedwith equal proportions of casein and the sodium salt of the styrenemaleic anhydride-methyl acid mateate copolymer has 4.5 times more resistance to abrasion than the yarns sized with an equivalent amount of casein solids per se or copolymer salt solidsper se. 7 I

The weaving efiicieney of the viscose sized with 6. thecaseimsodinm salt: Of. styrene-maleic anhydridemetlsyl acid maleate copolymer-size was excellent.

EXAMPLE I'II One hundred and fifty filament, forty." denier viscose yarns weresizedi with four separate solutions containing 3%- casein and 3% of the sodium salt of styrene-maleic anhydride-methyl acid maleate copolymer, prepared as described in Example I, to which had been added 5%, 10% and: 20 respectively, of sodium carbonate based on the total solidsin the solution. The yarns were sized with the above solutions according to the procedure described in Example II- The sized yarnswere tested on a Duplan adhesion tester to: abrasion resistance with the following results:

Cycles Abrasion (N0. of Sizing Composition Used Cycles Requlred-to Break Yarn) Solution of 3% casein and 3% of copolymer salt-+525,

Maroon... Solution of 3% casein and 3% of copolymer' salt+10% M1100 160 Solution of 3% casein and 3% of copolym NaiC' :r' 160 The above table when compared with the table in Example II shows that the sizing composition containing so- EXAMPLE IV Fifty parts of a dry mixture of 20 parts of casein, 10 parts of sodium carbonate and 20 parts of the sodium salt of a styrene-maleic anhydride-methyl acid maleatc copolymer (containing 54% combined styrene, 37% combined maleic anhydride and 9% combined methyl acid malea'te) were added to 1200 parts of water and the resuftin'g mixture was mechanically agitated at a temperature of 60 C. until a homogeneous solution was obtained, which required about 1 hour. The resulting solution, which contained about 1.6% casein, 1.6% of the copolymer salt and 0.8% sodium carbonate was then poured into the size box of a slasher and maintained at a temperature of F. Four thousand seven-hundred and seventy ends of filament-40 denier viscose were sized with the above solution by passing the yarns through the size solution at the rate of 40 yards per minute, squeezing the yarns at a pressure of 600 pounds per linear inch between squeeze rolls and thereafter passing the yarns over 7 dry cans which were maintained at temperatures of 145 F., F., F,, 200 F., 200 F., 200 F., and 160 F., respectively. The yarns were given 5.5% stretch during the sizing operation. The abrasion resistance of the yarns was comparable to the abrasion resistance of the yarns sized as described in Example III.

The sized yarns were woven on a conventional loom in atmosphere having a relative humidity of 65%. The weaving efiioicncy of such yarns was superior to that of yarns sized with the copolymcr salt alone which is in turn superior to the weaving eificicncy of yarns sized with casein alone. The size was readily removed from the fabric by a simple scouring operation.

EXAMPLE V One hundred and fifty filament, forty denier viscose yarns were sized with a solution containing 3% casein and 3% of the sodium salt of a styrene-maleic anhydride copolymer (containing 52% of combined styrene and 48% combined maleic anhydride), and 1.5% sodium carbonate according to the procedure described in Ex ample II. The sized yarns had substantially the same abrasion resistance and weaving eificiency as the sized yarns prepared according to Example 111.

As has been pointed out in the foregoing description, other alkaline peptizing agents may be used instead of sodium carbonate. Thus, sodium hydroxide, ammonia and triethanolamine are useful for this purpose. However, sodium carbonate is the only alkaline peptizing agent which markedly improves the abrasion resistance of the size of this invention. Therefore, sodium carbonate is unique for the purposes of this invention.

Various modifications and changes may be made in the compositions and processes of this invention as will be apparent to those skilled in the art to which they appertain without departing from the spirit and intent of the present invention. It is intended, therefore, that this invention be limited only by the scope of the appended claims.

What is claimed is:

1. A composition of matter comprising essentially a dry mixture of casein, a water-soluble alkali metal salt of a copolymer of (1) a substance selected from the group consisting of styrene and substituted styrene and (2) a substance selected from the group consisting of maleic anhydride, alkyl half esters of maleic acid, in which the alkyl group contains from 1 to 3 carbon atoms, and mixtures of said anhydride and half esters, and from 0.01 to 35% by weight, based on the total solids in the mixture, of sodium carbonate, said casein and said alkali metal salt of the copolymer being present in a weight ratio between 70:30 and 30:70.

2. A composition of matter comprising essentially a dry mixture of 70 to 30 parts by weight of casein, from 30 to 70 parts by weight of a water-soluble sodium salt of a copolymer of styrene, maleic anhydride and methyl acid maleate and from 5 to 25% by weight, based on the total solids, of sodium carbonate.

3. A composition of matter comprising essentially a dry mixture of 70 to 30 parts by weight of casein, from 30 to 70 parts by weight of a water-soluble sodium salt of a copolymer of styrene and maleic anhydride and from 5 to 25% by weight, based on the total solids, of sodium carbonate.

4. A textile warp sizing composition comprising essentially an alkaline aqueous solution of casein, a watersoluble alkali metal salt of a copolymer of (1) a substance selected from the group consisting of styrene and substituted styrene and (2) a substance selected from the group consisting of maleic anhydride, alkyl half esters of maleic acid, in which the alkyl group contains from 1 to 3 carbon atoms, and mixtures of said anhydride and said half esters, and from 0.01 to 35% of sodium carbonate, based on the total solids in said composition, said casein and alkali metal salt of the copolymer being preggntngn the solution in a weight ratio between 70:30 and 5. A textile warp sizing composition comprising essentially an alkaline aqueous solution of casein, a watersoluble sodium salt of a copolymer of styrene, maleic anhydride and methyl acid maleate and from 5 to 25% by weight of sodium carbonate, based on the total solids in said composition, said casein and said sodium salt of the copolymer being present in the solution in a weight ratio between 70:30 and 30:70.

6. A textile warp sizing composition comprising essentially an alkaline aqueous solution, of casein, a water-- soluble sodium salt of a copolymer of styrene and maleic anhydride and from 5 to 25 by weight of sodium car-- bonate, based on the total solids in said composition, said casein and the sodium salt of the copolymer being present in the solution in a weight ratio between 70:30 and 30:70.

7. A method of sizing textile warp yarns which comprises applying to said yarns a homogeneous composition consisting essentially of an alkaline aqueous solution of casein and a water-soluble alkali metal salt of a copolymer of (1) a substance selected from the group consisting of styrene and substituted styrene and (2) a substance selected from the group consisting of maleic anhydride, alkyl half esters of maleic acid, in which the alkyl group contains from 1 to 3 carbon atoms, and mixtures of said anhydride and half esters, said casein and said alkali metal salt of the copolymer being present in the solution in a weight ratio between 70:30 and 30:70, said composition being at a temperature of 120 to 180 F., removing said yarns from said compositions and drying the yarns.

8. A method according to claim 7 but further characterized in that the solution also contains from 0.01 to 35%. by. weight, based on the total solids in the composition, of an alkaline peptizing agent for the casein.

9. A method of sizing textile warp yarns which comprises applying to said yarns a homogeneous composition consisting essentially of an alkaline aqueous solution of casein and a water-soluble alkali metal salt of a copolymer of styrene, maleic anhydride and methyl acid maleate, said casein and said alkali metal salt of the copolymer being present in the solution in a weight ratio between 70:30 and 30:70, said composition being at a temperature of to F. and being supplied in an amount sufiicient to provide from about 2 to 12% by weight of solids, based on the weight of the yarns, removing said yarns from said composition and then drying the arns.

10. A method of sizing textile warp yarns which comprises applying to said yarns a homogeneous composition consisting essentially of an alkaline aqueous solution of casein and a water-soluble alkali metal salt of a copolymer of styrene and maleic anhydride, said casein and said alkali metal salt of the copolymer being present in the solution in a weight ratio between 70:30 and 30:70, said composition being at a temperature of 120 to 180 F. and being supplied in an amount sufficient to provide from about 2 to 12% by weight of solids, based on the weight of the yarns, removing said yarns from said composition and then drying the yarns.

11. A method of sizing regenerated cellulose textile warp yarns which comprises applying to said yarns a homogeneous composition consisting essentially of an alkaline aqueous solution of casein, a water-soluble alkali metal salt of a copolymer of (1) a substance selected from the group consisting of styrene and substituted styrene and (2) a substance selected from the group consisting of maleic anhydride, alkyl half esters of maleic acid, in which the alkyl group contains from 1 to 3 carbon atoms, and mixtures of said anhydride and said half esters, and from 0.01 to 35% by weight, based on the total solids in said composition, of an alkaline peptizing agent for said casein, said casein and said alkali metal salt of the copolymer being present in the solution in a weight ratio between 70:30 and 30:70, said composition being at a temperature of 120 to 180 F., removing said yarns from said composition and then drying the yarn.

12. A method of sizing regenerated cellulose textile warp yarns which comprises applying to said yarns a homogeneous composition consisting essentially of an alkaline aqueous solution of casein, a water-soluble alkali metal salt of a copolymer of (1) a substance selected from the group consisting of styrene and substituted styrene and (2) a substance selected from the group consisting of maleic anhydride, alkyl half esters of maleic acid, in which the alkyl group contains from 1 to 3 carbon atoms, and mixtures of said anhydride and said half esters, and from 5 to 25 by weight of sodium carbonate. based on the total solids in said solution, said casein and said alkali metal salt of the copolymer being present in the solution in a weight ratio between 70:30 and 30:70, said composition being at a temperature of 120 to 180 F., removing said yarns from said composition and then drying the yarns.

13. A method of sizing regenerated cellulose textile warp yarns which comprises applying to said yarns a homogeneous composition consisting essentially of an alkaline aqueous solution of casein, a water-soluble sodium salt of a copolymer of styrene, maleic anhydride and methyl acid maleate and from 5 .to 25% by weight of sodium carbonate, based on the total solids in said solution, said casein and sodium salt of the copolymer being present in the-solution in a weight ratio between 70:30 and 30:70. said composition being at a temperature of 120 to 180 F., removing said yarns from said solution and then drying the yarn.

14. A method of sizing regenerated cellulose textile warp yarns which comprises applying to said yarns a homogeneous composition consisting essentially of an alkaline aqueous solution of casein, a water-soluble sodium salt of a copolymer of styrene and maleic anhydride and from 5 to 25 by weight of sodium carbonate, based on the total solids in said solution, said casein and sodium salt of the copolymer being present in the solution in a weight ratio between 70:30 and 30:70, said composition being at a temperature of 120 to 180 F., removing said yarns from said solution and then drying the yarns.

15. A method of sizin g regenerated cellulose textile warp yarns which comprises applying to said yarns a homogeneous composition consisting essentially of an alkaline aqueous solution of casein, a water-soluble alkali metal salt of a copolymer of (1) a substance selected from the group consisting of styrene and substituted styrene and (2) a substance selected from the group consisting of maleic anhydride, alkyl half esters of maleic acid, in which the alkyl group contains from 1 to 3 carbon atoms, and mixtures of said anhydride and said half esters, and from 0.01 to by weight of sodium carbonate, based on the total solids in said composition, said casein and said alkali metal salt of the copolymer being present in the solution in a weight ratio between :30 and 30:70, said composition being at a temperature of to F., removing said yarns from said composition and drying the yarn.

References Cited in the file of this patent Number UNITED STATES PATENTS OTHER REFERENCES Mattiello, Protective and Decorative Coatings, vol. III, page 464, Wiley 1943. 

7. A METHOD OF SIZING TEXTILE WARP YARNS WHICH COMPRISES APPLYING TO SAID YARNS A HOMOGENEOUS COMPOSITION CONSISTING ESSENTIALLY OF AN ALKALINE AQUEOUS SOLUTION OF CASEIN AND A WATER-SOLUBLE ALKALI METAL SALT OF A COPOLYMER OF (1) A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF STYRENE AND SUBSTITUTED STYRENE AND (2) A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF MALEIC ANHYDRIDE, ALKYL HALF ESTERS OF MALEIC ACID, IN WHICH THE ALKYL GROUP CONTAINS FROM 1 TO 3 CARBON ATOMS, AND MIXTURES OF SAID ANHYDRIDE AND HALF ESTERS, SAID CASEIN AND SAID ALKALI METAL SALT OF THE COPOLYMER BEING PRESENT IN THE SOLUTION IN A WEIGHT OF RATIO BETWEEN 70:30 AND 30:70, SAID COMPOSITION BEING AT A TEMPERATURE OF 120 TO 180* F., REMOVING SAID YARNS FROM SAID COMPOSITIONS AND DRYING THE YARNS. 